Recently, vehicle navigation systems have become more popular and affordable for most vehicle drivers. The navigation system can, not only determine the driver's current position by utilizing the Global Positioning System (GPS), but also provide different routing information between the vehicle's current position and the destination. In order to perform above noted functions, the navigation system is usually equipped with navigation computer programs and one or more detailed database to store and provide information on maps, map attributes, road networks, geographical features and points-of-interests (POI), etc.
Generally, when a destination is specified by the driver, the navigation system generates a calculated route which is a preferred or optimized route to the destination. The calculated route is usually displayed associated with a map in a highlighted manner on a display unit in the vehicle. However, even with the aid of the navigation system, the driver may still miss the destination if the destination is new to the driver or the driver is unfamiliar with the environment nearby the destination.
Even though the driver is relatively familiar with the environment nearby the destination, if he approaches the destination in a direction different from that of the past experience, he may lose sight of the destination. Under these circumstances, the driver may need more geographical information near the destination, such as major streets, landmarks, brand POIs, etc., to help the driver visualize the environment of the destination. With such visualized information around the destination, the driver can have better sense when the vehicle is approaching the destination.
In order to provide the driver better sense and help the driver visualize the environment near the destination, a map with dynamic scale to display some geographical features near the destination has been developed in navigation systems. U.S. Pat. No. 5,699,255 issued to Ellis et al. discloses a navigation system which is able to tailor the map information and then transmits the information to the driver. In one embodiment, the navigation system of Ellis et al. provides the map information of varying degrees of resolution and detail.
However, as shown in FIGS. 1a and 1b of Ellis et al., the driver has to manually operate the pull-down window to select the scale of the map resolution 110 and the detail level 120. In other words, the map resolution as well as the details are not dynamically changed when the vehicle is approaching the destination. Further, the driver may be distracted from the safe driving when he has to manually operate the pull-down window in the system.
U.S. Pat. No. 5,450,343 issued to Yurimoto et al. discloses a navigation device adapted to display a starting point and a route search beginning point at the highest possible scale. The navigation device can display a part of the searched route (calculated route) and the vehicle's present position at the highest possible scale when the vehicle is traveling on the searched route. As shown in FIGS. 2a and 2b, when the vehicle 210 is approaching the route search beginning point 220, the map scale is changed at the highest possible level in a predetermined area 240 to help the driver better visualize the environment of the search beginning point 220 and the route 230.
Although the map scale in Yurimoto et al. is changed dynamically, the map is designed to accommodate some specific points, such as a starting point and a route search beginning point, or a search ending point and a destination point, at the highest possible scale. However, if the search ending point is far away from the destination point, even though the map is changed to the highest possible scale, it may still be difficult for the driver to visualize the environment of the destination. Furthermore, the search ending point may not be a major street or a landmark associated with the destination, thus, it does not provide substantial help to the driver to understand more about the environment of the destination.
Therefore, there remains a need for a new and improved map displaying apparatus and method for a navigation system which provides the driver more geographical or environmental information close to the destination to help the driver better visualize the arrival of the destination, such that the possibility for the driver to miss the destination will be significantly reduced.